Automatic sectionalizing switch



Nova 12, 1957 J. M. WALLACE 2,813,166

AUTOMATIC SECTIONALIZING SWITCH Filed Jul 23, 1952 Fig.|.

Automatic Reclosing Circuit Breaker WITNESSES: I v i0 28 INVENTOR d Fi.4, JomesMWoHoce. Q Ufim g at? 6 ATTORNE United States Patent AUTOMATICSECTIONALIZING SWITCH James M. Wallace, Montclair, N. J., assignor toWestinghouse Electric Corporation, East Pittsburgh, Pa., a corporationof Pennsylvania Application July 23, 1952, Serial No. 300,380 12 Claims.(Cl. 200-88) My invention relates, generally, to circuit interrupters,and it has reference, in particular, to automatic section alizingswitches which open when the circuit in which they are connected isdeenergized, and reclose a predetermined time after the circuit isreenergized.

In distribution systems it is fairly common to use automatic reclosingcircuit breakers to provide protection for difierent sections of thesystem. Because of the use of many periodic types of loads, such asrefrigerators, pumps, blowers and the like, the diversity of the load onthe system may be largely lost if the system is deenergized for anylength of time. normally only a relatively small percent of such loadswill be energized at any one time, whereas after an extended outage,such as may be caused by a fault of sufficient duration to cause thereclosing circuit breaker to lock open, substantially all of these loadswill be connected to the circuit awaiting its reenergization. This willoften result in such a heavy in-rush of load current that the reclosingcircuit breaker is over-loaded, and again operates to the locked openposition. To prevent such operation of the reclosing circuit breaker,automatic sectionalizing switches may be used at different points alongthe system, which open only when the circuit is deenergized for asufficiently long time, and reclose a predetermined time after voltageis reapplied to the circuit. This provides for sequentially reconnectingseveral adjacent sections of a distribution circuit, so that thereclosing circuit breaker is required to handle only a limited portionof the total load on the circuit at any one time.

Accordingly, it is an object of my invention to provide in a novelmanner for delaying the reclosing of an automatic sectionalizing switchby using the thermal capacity of the whole switch for delaying reclosingof the switch after it has opened.

Yet another object of my invention is to provide in a circuitinterrupter for using a plurality of biasing means of differentstrengths for operating a movable contact, and for selectivelycontrolling the effectiveness of the different biasing means.

It is also an object of my invention to provide in a circuit interrupterfor biasing a movable contact in opposite directions, and for utilizingtime delay means for rendering one of the biasing means inoperative apredetermined time after the circuit is energized.

One important object of my invention is to provide in a circuitinterrupter for utilizing a heater to raise the temperature of the oilwhen the interrupter is open and the circuit is energized, and for usingthermally responsive means for delaying reclosing of the interrupter inaccordance with a temperature condition of the oil.

Yet another important object of my invention is to provide in a circuitinterrupter for using a thermally responsive latch for connecting amovable contact to a contact actuating member, and for releasing thelatch when the This results from the fact that interrupter is open andthe circuit to which is it connected is energized, so as to effectmovement of the movable contact to the closed position a relatively longtime after the circuit is energized.

Other objects will in part be obvious, and will in part be explainedhereinafter.

In accordance with one of the embodiments of my invention, a movablecontact of an automatic sectionalizing switch may be normally biased tothe closed position. Biasing means may be provided for actuating acontact operating member to a contact-opening position, andelectroresponsive means may be utilized to normally render such biasingmeans inoperative so long as current flows through the switch. Thecontact-operating member may be connected to the moving contact by meansof a thermally responsive latch, and a heater may be connected in shuntrelation with the contacts for heating the insulating oil in which theswitch is immersed so as to provide for releasing the latch to permitclosing of the contacts a relatively long time after the circuit hasbeen reenergized.

For a more complete description and understanding of the invention,reference may be made to the following detailed description and theaccompanying drawing, in which:

Figure 1 is a substantially vertical sectional view of a switchembodying the invention in one of its forms;

Fig. 2 is an enlarged sectional view taken along the line IIII of Fig.1;

Fig. 3 is a diagrammatic view of a distribution system illustrating anapplication of the sectionalizing switch of Fig. 1; and

Fig. 4 is an enlarged view taken along the line IV-IV of Fig. 1.

Referring to Fig. 1 of the drawing, the reference numeral 10 may denotegenerally an automatic sectionalizing switch which may be disposed in asubstantially cylindrical metal container or tank 12, having anoutwardly projecting flange 13 around the upper edge. Suitable brackets14 may be secured to the container 12 for supporting it from a pole orthe like. The container 12 may be filled with a suitable insulatingfluid such as oil or the like, designated by the numeral 15. Asubstantially cylindrical insulating liner 17 may be disposed about theinterior of the walls of the tank, and the bottom thereof may beprovided with an insulating liner 18 of any suitable material such asfiber or the like.

The container 12 may be provided with a suitable cover 20, which may besecured to the flange 13 in any suitable manner such as by means ofbolts (not shown). Insulating bushings 22 and 24 may be mounted on thecover 20 for supporting conductors 25 and 26, the bushings extendingthrough cover so as to permit entrance of the conductors 25 and 26 tothe interior of the container 12.

A movable contact member such as the switch blade 28, having a movablecontact 30 at one end, may be pivotally mounted by means of a pivot 32at the other end to the inner end of the conductor 25. Biasing meanssuch as a spring 33 may be utilized for urging the blade 28 in acounter-clockwise direction to engage a stationary contact 34 which maybe supported on the inner end of the conductor 26 but insulatedtherefrom by means of insulation 35. The spring 33 may be connectedbetween the blade 28 and a lug 31 adjacent the lower end of conductor25.

In order to provide for actuating the switch blade 28 to the openposition, an operating arm 37 may be disposed alongside the blade,pivotally mounted on the pivot 32, and connected by means of a link 39to the armature 40 of solenoid 42 which is connected in series with theconductor 26 and the stationary contact 34. A coil spring 44 disposedwithin the bore of the solenoid normally biases the operating arm 37 ina clockwise direction. The spring 44 is sufiiciently stronger than thespring 33 to overcome the effect of the latter spring. The solenoid 42may be supported from the cover 20, being disposed about a cylindricalextension 46 of a plate 48 having an upwardly projecting lug 50 thereonto receive a pivot 52 which passes through a downwardly extendinginsulating support 54 which may be secured to a boss 55 on the undersideof the cover 20. The armature 46 may be disposed to have a relativelytight fitin the cylindrical extension 46, and means such as a ball-checkvalve 56 may be provided in conjunction with a bore 57 in the plate 48,so as to provide a unidirectional dashpot action for delaying downwardmovement of the armature 40. The lug 31 may be extended to projectbeneath the blade 28 and arm 37 to provide a stop 58 to limit downwardmovement thereof.

The operating arm 37 may be normally operatively connected to the switchblade 28 by'means of a releasable latch 64). The latch 60 may comprise athermally-responsive bimetallic support 62 mounted on the operating arm37, and a latch projection 64 which projects over the top side of theswitch blade 28. The bimetallic support 62 may comprise a pair oflaminations of materials having difierent rates of expansion which aresuitably secured together in a manner well known in the art. In thepresent instance, for example Figs. 2 and 4, the left-hand laminationsmay be a brass or some such metal having a relatively high coefiicientof expansion, while the righthand lamination is made of iron or steel,having a lower coeflicient of expansion. In order to provide arelatively long time delay on the order of from 1 to substantially 3hours in reclosing the switch after the circuit is reenergized, thethermal capacity of the entire switch may be used to delay reclosing,and means such as an electric heater or resistance element 66 may bedisposed in the insulating oil and connected in circuit with theconductors 25 and 26 in shunt relation with the contacts 30 and 34 so asto be energized only when the contacts are open and the circuit isenergized, to raise the temperature of the oil and operate the latch 69.Since the latch 60 is spaced from the heater 66, and the temperature ofthe oil is substantially that of the entire switch, operation of thelatch 60 is basically dependent on the temperature and thermal capacityof the entire switch. By changing the spacing of the heater 66 and latch60, the delay in operation and reset may be widely varied, from a fewminutes to as much as 2 or 3 hours.

Referring to Fig. 3, it will be seen that several of the automaticsectionalizing switches may be connected between adjacent sections 76,72, 73 and 74 of a distribution circuit which is connected by means ofan automatic reclosing circuit breaker 75 to a source conductor 76. Thereclosing circuit breaker 75 may be of any of the types which are wellknown in the art, and provide for one or more instantaneous openings andone or more delayed openings in response to a fault before the breakeris locked in the open position. The dashpot action of the armatures 46is such that the switches 10 do not open in response to the severalautomatic openings of the breaker 75. When the reclosing circuit breakerlocks open, the switches 16) open after time delay afforded by thedashpot action of armatures 46 as spring 44 overcomes spring 33 andseparate the contacts 30 and 34. It will be noted that this action takesplace only when the circuit is deenergized.

With the sectionalizing switches 10 in the open positions, as shown, itwill be seen that the heater 66 will be connected in series circuitrelation with solenoid 42 between the conductor 76 and the load 78 ofthe first switch when the reclosing circuit breaker 75 is closed.Accordingly, the oil of this switch may be slowly heated. Inasmuch asthe heaters 66 may have a relatively high resistance compared with thatof the load (five to ten thousand ohms, for example), only limitedvoltages will be applied under these conditions to the heaters of theother switches, and only limited current can flow through solenoid 42.

Since the coil spring 44 is stronger than the spring 33 it operated theoperating arm 37 in a clockwise direction carrying the switch blade 23with it to the open position as soon as the circuit was deenergized toengage stop 58. After a predetermined time, when the heater 66 hasraised the temperature of the bimetallic support 62 to a predeterminedvalue, the latch 60 will be actuated by the bimetallic support 62 in adirection to release the switch blade 28. The spring 33 is thereuponeffective to operate the switch blade in a counter-clockwise directionto bring moving contact 30 into engagement with the stationary contact34. The heater 66 is thereupon shunted and section 72 of thedistribution circuit will thereupon be fully reenergized. The solenoid42 of the first switch will therefore be sufficiently energized to beactuated to compress the coil spring 44 and operate the arm 37 in acounter-clockwise direction to a position alongside the switch blade 28.The oil 15 carries heat away from the latch support, and after apredetermined delay it operates to reset the latch 60. The othersectionalizing switches will operate in sequence, in a similar manner,so that the several sections of the distribution circuit aresequentially reenergized after an outage caused by opening of thereclosing circuit breaker 75.

From the above description and the accompanying drawing it will beapparent that I have provided in a simple and effective manner forsectionalizing a distribution circuit to facilitate reconnection of theload after an outage. By varying the proximity of the heater and latch,and thereby utilizing the thermal capacity of a major part of, or theentire switch device, in the manner hereinbefore described, time delaysvarying from a few minutes to a relatively great magnitude may bereadily obtained. Periods up to as much as l to 3 hours are easilyobtainable in this manner.

Since certain changes may be made in the above described constructions,and different embodiments of the invention may be made without departingfrom the spirit and scope thereof, it is intended that all the mattercontained in the above description and shown in the accompanying drawingshall be considered as illustrative and not in a limiting sense.

I claim as my invention:

1. In a switch, a container for an insulating fluid, a pair ofterminals, a stationary contact connected to one terminal and supportedin the fluid, a movable contact connected to the other terminal andpivotally supported by a pivoted arm for engaging the stationarycontact, a spring biasing the arm to actuate the movable contact towardthe stationary contact, an operating arm pivotally disposed alongsidethe arm of the movable contact, an additional spring stronger than thefirst mentioned one biasing the operating arm in a direction to separatethe movable contact from the stationary contact, a thermoresponsivelatch normally connecting the operating arm and arm of the movablecontact, electroresponsive means connected in series with the contactsand having an armature connected to the operating arm for rendering theadditional spring ineffective when energized, and a heater connectedbetween the contacts for efiecting release of the thermoresponsive latchwhen the temperature of the fluid reaches a predetermined value.

2. An automatic load pick-up switch for a circuit comprising, acontainer for an insulating fluid, a cover for said container, a pair ofterminal conductors, insulating bushings for providing insulatedpassages through the cover for said conductors, a stationary contactmounted on one bushing in the container, a switch blade pivotallymounted on the other bushing for engaging the stationary contact,meansvbiasing the switch blade to engage the stationary contact, anoperating arm pivotally mounted alongside the switch blade,electroresponsive means including a solenoid connected in series withthe conductor of said one bushing and the stationary contact and havingan armature connected to the operating arm to operate it in the contactclosing direction when suflicient current flows in the solenoid, aspring biasing the armature in the contact separating direction, dashpotmeans retarding movement of the armature in response to the springaction, a thermoresponsive latch normally connecting the operating armand the switch blade, and a heater connected in series with theterminals for rendering the latch inoperative when the circuit isenergized and the contacts are separated.

3. In a switch device, a container for an insulating fluid, separablecontacts disposed in said container, an operating mechanism for saidcontacts, means biasing the operating mechanism to close said contacts,operating means, means biasing the operating means in a direction toopen the contacts, series solenoid means operable when energized tooppose said biasing means, means connected to heat the fluid in thecontainer in response to application of voltage to the switch devicewhile the contacts are separated, and releasable means connecting theoperating means to the contact operating mechanism responsive to anincrease in the temperature of the fluid for releasing the contactmechanism and rendering the closing means eflective.

4. A circuit interrupter comprising, separable contacts, means biasingthe contacts closed, operating means ineluding electroresponsive meansconnected in series with the contacts responsive to a predeterminedvalue of current for etfecting operation of said contacts in onedirection to close them, means biasing the operating means to operatethe contacts in the other direction, heating means for said interrupterresponsive to energization of said circuit, and releasable meansresponsive to an increase in temperature condition resulting fromoperation of said heating means, for disconnecting the contacts from theoperating means and rendering the biasing means effective to close thecontacts.

5. In a switch, separable contacts, a container maintaining aninsulating fluid about said contacts, operating means operable to closesaid contacts, actuating means operable to opening said contacts, meansoperable to heat the insulating fluid, thermal releasable meansconnecting the actuating and operating means together responsive to apredetermined rise in temperature condition of the fluid for releasingthem and rendering the operating means operative, and current responsivemeans connected in series with the contacts opposing said actuatingmeans.

6. A switch comprising, a container for an insulating fluid, a cover forsaid container, separable contacts, operating means for said contactssupported in the insulating fluid from said cover, means biasing saidoperating means to close said contacts, opening means opposing saidbiasing means, current responsive means opposing said opening means, aheater operable to heat the fluid in response to application of voltageto the switch only when the contacts are open, and thermoresponsivemeans releasably connecting the biasing means to the operating meansoperable to render the biasing means effective to close the contacts inresponse to a predetermined increase in the temperature condition ofsaid fluid.

7. In a switch, separable contacts, operating means therefor, meansbiasing said operating means to close the contacts, additional biasingmeans stronger than the aforesaid biasing means opposing said biasingmeans to open said contacts, series connected electroresponsive meansresponsive to energization opposing said additional biasing means, aheater connected between said contacts operable in response toapplication of voltage to the switch when the contacts are open to heatthe switch, and thermal releasable means normally connecting theadditional biasing means to the operating means operable in response toa predetermined temperature condition of the switch to release them andrender the biasing means effective to close the contacts.

8. In an automatic load pick-up switch, a container for an insulatingfluid, separable contacts operable to connect the load to a source,operating means therefor, actuating means including electroresponsiveholding means connected in series with and holding the contacts closedand opposing biasing means effecting separation of the contacts inresponse to deenergization of a circuit, means actuating the operatingmeans and reclosing said switch, a heater responsive to reenergizationof the circuit while the load contacts are separated to supply heat tothe insulating fluid, and thermoresponsive latch means connecting theoperating means to the actuating means operable in response to apredetermined thermal condition of the fluid to release them and renderthe reclosing means operative.

9. A switch comprising, separable contacts, operating means including apair of pivotally mounted members having opposing biasing means foreffecting relative movement of said members in opposite directions, aheater responsive to application of voltage to said switch for supplyingheat to the switch, and means for effecting operation of said operatingmeans including a thermoresponsive latch element normally connecting themembers together operable in response to a predetermined rise in thermalcondition of the switch to release said members to permit one of thebiasing means to close said contacts 10. In a switch, a container for aninsulating fluid, separable contacts disposed in the fluid in saidcontainer, operating means for said contacts, means biasing saidoperating means to open said contacts, series electroresponsive meansfor opposing said biasing means, heating means connected between thecontacts for heating the fluid in response to energization of a circuitwhen the contacts are open, additional biasing means biasing theoperating means for closing said contacts, and releasablethermoresponsive means normally connecting the biasing means to theoperating means operable in response to a predetermined rise intemperature condition of the switch to release them and render saidadditional biasing means effective.

11. A switch comprising, a stationary contact member, a movable contactmember, an operating mechanism for the movable contact member, meansbiasing the operating mechanism to urge the movable contact member toengage the stationary contact member, actuating means for actuating themovable contact member to separate from the stationary contact member,current responsive means opposing the actuating means when the switch isclosed, a heater connected across the contacts operable to supply heatto the switch while the contact members are separated and the circuit isenergized, and thermal releasable means connecting the actuating meansand the movable contact member, said releasable means being operable torelease the movable contact member and the actuating means in responseto a predetermined rise in temperature condition of the switch.

12. A switch comprising, separable contacts, operating means for thecontacts, biasing means for actuating the operating means and closingthe contacts, actuating means operable to overcome the biasing means andactuate the operating means to separate the contacts, a solenoid havingan armature connected to the actuating means operable to oppose andrender the actuating means inoperative so long as the solenoid remainsenergized, thermoresponsive means including a releasable elementnormally connecting the actuating and operating means operable inresponse to predetermined rise in the temperature condition of theswitch to release them and render the actuating means inefiective toopen the contacts, and heater means connected between the contacts forheating the switch while said contacts are open to effect operation ofthe thermoresponsive means.

References Cited in the file of this patent UNITED STATES PATENTS HillJan. 26, 1909 Brobst Mar. 24, 1925 Parks et a1 Aug. 15, 1933 Walle Dec.30, 1941 10 Frank et a1 Feb. 24, 1942 Rawlins et a1 Dec. 1, 1942 8 Grantet al. Jan. 12, 1943 Leonard June 20, 1944 Ludwig et a1 Oct. 24, 1944Link Nov. 6, 1945 Kyle, Jr. et a1. Jan. 18, 1949 Moorhead Oct. 11, 1949Lincks Octv 23, 1951 Edwards et a1 Mar. 20, 1956 FOREIGN PATENTS GermanyJan. 10, 1924 Germany June 24, 1907

